Engine Overheating Issues (1 Viewer)

[M P]

Hey all,

I've been dealing with an engine temp issue for a while ('89 FJ62 3FE 258,000miles). Most notably when going uphill, the temp will rise and the needle will rest on the hash just before the red. Going downhill it cools. I've taken radiator temps with an IR Thermometer of 220-226 degrees F when it's at it's hottest. It hasn't boiled over (yet). No overt signs of cross contamination in the coolant well or oil.

The entire cooling system is new/has been replaced. Radiator, fan, fan clutch, water pump, water sending unit, hoses.. the whole shebang. Fan clutch is OEM and good.

So - it's gotta be a head issue, right? Either the head gasket or a micro fracture in the head -which, I know, isn't supposed to happen, but... what else could it realistically be? My mechanic tried the combustion leak test on the radiator, and got a negative result, but as I understand it, it's hard to get a definitive result from those tests.

Second question is - do I just have the head done - a $3000 job, or will that just possibly shift compression issues to the lower? Do I need to shell out $5000 for a total engine rebuild?

OR - can any of you convince my wife that an $18,000 V8 swap is the best course of action?

M

 

[SteveH]

I would remove and test the thermostat, and then install a 180F t-stat from an FJ60, with new gaskets and the rubber washer/disk, and see how it runs.

Is your lower radiator hose blazing hot, as well as the top? If not, then your radiator may be passing heat well through the radiator (for one reason or another). FWIW - I saw 15 degree hotter temps with my IR heat gun when the engine was running, due to the air flow over the temp gun. When I shut the engine off, the temp gun read lower.

Steve

 

[M P]

I would remove and test the thermostat, and then install a 180F t-stat from an FJ60, with new gaskets and the rubber washer/disk, and see how it runs.

Is your lower radiator hose blazing hot, as well as the top? If not, then your radiator may be passing heat well through the radiator (for one reason or another). FWIW - I saw 15 degree hotter temps with my IR heat gun when the engine was running, due to the air flow over the temp gun. When I shut the engine off, the temp gun read lower.

Steve

I'm lucky to live in LA where there are a few reputable Land Cruiser resources. I had the same idea and went to pick up the 180 degree thermostat and gaskets from Specter Offroad and ended up talking to Kurt, their mechanic... he took me to out back to their shop, dug out an old thermostat housing from a dumpster, removed the thermostat, and proceeded to cut/grind it till the center could be removed. He deburred it and handed it to me and said, "Here. This is how I run mine."
The idea being that the coolant will flow constantly but the empty housing will constrict the flow just enough... I wouldn't trust him except for the fact that his whole life has been wrenching on cruisers. He's fully restored over 30 of them. He also worked at TLC as a mechanic for a long time, as did my mechanic... and when I handed my mechanic the thermostat-husk the next day he didn't even blink and agreed to install it to see what we'd see.

The avg running temp of the engine is lower than before (as you'd expect), but it still gets hotter than my mechanic expected it to (middle hash on flat highway) and the temp still rises considerably going up steep hills (halfway between the last 2 hash marks before red).

I will check the lower hose and try checking temp w/ the engine off. Thx,

 

[OSS]

Replace the radiator and fan clutch with new and put the correct 190° thermostat back in (un modified). When the engine is truly running hot, all the thermostats are wide open: the 190, the 180 and a drilled out thermostat. You're not doing the engine any favors by removing the core of the thermostat. Say hello to sludge, poor mpg, and increased engine wear.

The problem isn't the thermostat.
The problem COULD be the head gasket having clogged cooling holes. If in the past, the previous owner mixed orange Dexcool coolant with green glycol coolant, the ensuing goop that develops from the incompatible chemistries will eventually clog up most of the smaller cooling holes in the head gasket- and assuredly prevent the head from getting adequate coolant flow - thus running hot.

My course of action would be to replace the radiator with a new CSF2708 and see what happens. If no improvement, remove the head and carefully examine & replace the head gasket. If the head gasket is replaced- do not use that piece of crap aftermarket head gasket SOR sells. Use only the Toyota gasket (not sold in a kit)

 

[M P]

Replace the radiator and fan clutch with new and put the correct 190° thermostat back in (un modified). When the engine is truly running hot, all the thermostats are wide open: the 190, the 180 and a drilled out thermostat. You're not doing the engine any favors by removing the core of the thermostat. Say hello to sludge, poor mpg, and increased engine wear.

The problem isn't the thermostat.
The problem COULD be the head gasket having clogged cooling holes. If in the past, the previous owner mixed orange Dexcool coolant with green glycol coolant, the ensuing goop that develops from the incompatible chemistries will eventually clog up most of the smaller cooling holes in the head gasket- and assuredly prevent the head from getting adequate coolant flow - thus running hot.

My course of action would be to replace the radiator with a new CSF2708 and see what happens. If no improvement, remove the head and carefully examine & replace the head gasket. If the head gasket is replaced- do not use that piece of crap aftermarket head gasket SOR sells. Use only the Toyota gasket (not sold in a kit)

NEW Radiator, NEW fan clutch, and NEW 190 thermostat (all OEM) was what I was running before (the whole dang cooling system was replaced w/ NEW OEM)- it was still overheating.

Thx for the warning re: the modified thermostat, though.. I'll probably put the still working unmodified 190 degree thermostat back in soon.

And thx for the advice re: the head gasket. Will do.

 

[hjdca]

Sorry for the 1 month later reply, but, I would bet that the new fan clutch is not working correctly. Is it roaring at startup like it should ? Try a Aisin FCT-049, it is the best ones for our 60s.
Note: I had the coolest running Landcruiser around. I remember my clutch fan roaring at startup. Last year I noticed it running a little hotter in the summer. This year, it heated up to 3/4 on the gauge climbing up to Lake Tahoe. I suspected my radiator, etc... . Then, I remembered the roaring at startup. Sure enough my original stock Clutch Fan was not roaring anymore and not locking up tight like it used to. It just wore out the last few years.
Note2: I have also heard of new fan clutches not having enough fluid in them or not working correctly.
Note3: Anytime there is a "running hot" problem with these 60's, most of the time, it is the clutch fan not working properly. You should check it well for proper operation.

 

[M P]

Thanks so much. It’s definitely worth a shot before exploring an engine rebuild. I appreciate it.

By the way - last big trip I did was up to Tahoe earlier this summer - the peg lived on the hash just before the red the entire trip up. My wife was just off the plane from 2 months working overseas. I was convinced we were gonna end up sitting on the side of the highway - but thankfully the old girl (meaning the truck, not my wife) pulled through.

 

[SHIfTHEAD]

So when you are going up hill, you are moving at say 60mph? If so then airflow won't be the issue I don't think. How does it run otherwise? Smooth idle, good acceleration? Any modification to the intake or exhaust? Still have the smog pump/system on the truck? Just wondering if you have a lean condition that is exacerbated by load.

 

[M P]

Smooth idle. Good acceleration. Runs really well. Replaced the Cats a year or so ago (CA compliant)

 

[M P]

No mods to intake. Passed CA smog so I assume still have smog pump

 

[hjdca]

Try this to validate whether your fan clutch is working properly. Go out on a hot day and put around at low rpm. Watch your temp gauge. It is probably at the first hash. Then, do the same trip in a much higher gear, reving out, but, going slow. If the temp goes up another hash mark or so, your clutch fan is not up to snuff. The high rpm, low speed, and hot weather should have the clutch fan locked up and the fan moving tons of air. If it is not, that is your issue. If you get another one, don't mess around with the Aisin FCT-017, go directly to the Aisin FCT-049 clutch fan. It is the best one for our 60s, fits perfect, and works great. Here are some pics of the FCT-049, you can see how substantial it is.

 

[hjdca]

Also, check your belt tension on the new clutch fan you already put in. If the belt is too loose, it will cause the same symptoms as a bad fan clutch. To easily check this, put a wrench on the clutch fan bolt and try to loosen it or tighten it. If the whole pulley moves with not much effort, your belt has stretched and you need to tighten it using the alternator adjustment screws. If the belt and fan clutch are new, It could be that the belt was not put on that tight, then, also stretched and is now too loose.

 

[M P]

Thanks so much for taking the time to advise me on this - I really appreciate it. Definitely not hearing the "roar" when I start the engine. Will check belt tension and try "putting" around to check temps this afternoon - as it's a hot one here in SoCal. Again - many thanks - will keep you appraised of the progress....

 

[hjdca]

I bet it is the belt tension. This has happened to me before also. These V-belts stretch, serpentine belts not so much. A few months down the road after a belt change, you have to tighten them again. On the bottom of the alternator, there is a lock bolt (12mm), loosen that, then, there is another 12mm bolt on the other side of the alternator facing the wheel well. That is the adjustment screw. Screw that clockwise until the belt gets tight (1" of play), then, retighten the front lock bolt. Go back and put a wrench on the clutch fan bolt and try to tighten it.... if the pulley does not move, then, the clutch fan should not slip at high rpm.

 

[hjdca]

Here is a comparison of my 3FE original stock '88 FJ62 Fan Clutch (red hub) to the 3FE FJ80 Aisin FCT-049 (green hub). I believe the original red hub piece is similar to a Aisin FCT-017, but, mine is the original stock Toyota fan clutch that was shipped with my truck. The FCT-049 is much more substantial and operates more smoothly -- not so abrupt on the on and off. A few years back the original red hub would roar at startup and when it switched on in the heat. The green hub engages more smoothly and locks up pretty good by the time the gauge goes to half way on the gauge with the air conditioning on in traffic. It does not really roar on startup like my original red hub did. In 100 deg. weather with the green hub and the stock thermostat, the gauge hangs around between the first and second hash mark (half way). If it creeps all the way up to half on the gauge, more air starts moving and you can watch the gauge come down below half again.









Here you can see the green hub FCT-049 has the same spacing as the stock FJ62 red hub Fan Clutch.

 

[chesshircat]

Check your temp sending unit too. I fought an overheating issue driving from CA to VA, replaced the entire cooling system along the way, when i got home figured out it was the sending unit.

 

[g-man]

Easy enough to ohm test the sender. This on a 2f ...not sure if it's the same for a 3fe

 

[jakerudy]

Shortly after I bought my FJ60 I replaced every radiator hose, oil cooler hoses, heater hoses, thermostat, and an aftermarket radiator cap. This was over 20 years ago with the 2F. Driving across Texas in 100+ temps it started to overheat at 70 mph. When I would slow down it would cool the engine.

Somewhere in west Texas it hit me that it might be cavitation in the water pump. Bought a Toyota radiator cap in New Mexico and it never happened again.

 

[M P]

Thanks. New OEM radiator cap on there. Someone else had advised me to try that a while back... eventually this mystery will be solved. I’ve just put so much $$$ into replacing the entire cooling system, it’s frustrating to have to spend more. But, it’s gotta get done one way or another... thanks for the reply.

 

[M P]

Easy enough to ohm test the sender. This on a 2f ...not sure if it's the same for a 3fe
View attachment 2070440

Thanks. It’s a new sending unit, but maybe it’s bad. Will definitely check it out. Appreciate it